Pros
I am in a medical PA role in the NHS. If you are hardworking, efficient, patient focussed and caring this is a very rewarding job. Even today there is still good security of employment, great annual leave allowances, parental leave and generous sick leave, along with an excellent pension scheme, in all very good terms and conditions. I would also struggle to find a PA role in another industry matching the salary You are left to get your work done without being "watched over" by management. Working in a large hospital along so many different specialisms and colleagues is interesting.
Cons
Sometimes patients can be rude, I guess like customers anywhere. They can also be anxious, upset and distressed, understandably, and you can be left to deal with things on your own; sometimes you can feel a little isolated. If you are not dedicated it can be difficult to get the job done competently, as the work load does tend to be large. It is the norm to work through breaks, come to work earlier than the start of the shift, etc, but if you are dedicated to patient care and your team it is worth it.